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[209.85.128.181]) by smtp.gmail.com with ESMTPSA id 00721157ae682-712c4c1f62fsm24607747b3.121.2025.06.25.07.28.33 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 25 Jun 2025 07:28:33 -0700 (PDT) Received: by mail-yw1-f181.google.com with SMTP id 00721157ae682-70e5d953c0bso20235037b3.1 for ; Wed, 25 Jun 2025 07:28:33 -0700 (PDT) X-Received: by 2002:a05:690c:6701:b0:70f:83ef:ddf7 with SMTP id 00721157ae682-71406cb55e0mr48485717b3.13.1750861713116; Wed, 25 Jun 2025 07:28:33 -0700 (PDT) List-Id: User questions List-Archive: https://lists.freebsd.org/archives/freebsd-questions List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: freebsd-questions@freebsd.org Sender: owner-freebsd-questions@FreeBSD.org MIME-Version: 1.0 References: In-Reply-To: From: Tomek CEDRO Date: Wed, 25 Jun 2025 16:28:22 +0200 X-Gmail-Original-Message-ID: X-Gm-Features: AX0GCFsl2zHKNoOP_eN8b-FO4mGoTMHCDepNDvldf85qcQqVteXSAdj_BX1nORQ Message-ID: Subject: Re: Wiping a disk partition To: Odhiambo Washington Cc: questions Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 4bS41g5w29z3Xy1 X-Spamd-Bar: ---- X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[]; ASN(0.00)[asn:15169, ipnet:2607:f8b0::/32, country:US] On Wed, Jun 25, 2025 at 12:18=E2=80=AFPM Odhiambo Washington wrote: > > I have this: > ``` > root@gw:/home/wash # df -h > Filesystem Size Used Avail Capacity Mounted on > /dev/ada0p2 1.8T 552G 1.1T 33% / > devfs 1.0K 0B 1.0K 0% /dev > fdescfs 1.0K 0B 1.0K 0% /dev/fd > procfs 8.0K 0B 8.0K 0% /proc > linprocfs 8.0K 0B 8.0K 0% /compat/linux/proc > linsysfs 8.0K 0B 8.0K 0% /compat/linux/sys > /dev/ada1p2 1.8T 856G 802G 52% /disk2 > ``` > > What is the fastest way to wipe all data on /dev/ada1p2? The fastest way would be to overwrite partition with zeros: dd if=3D/dev/zero of=3D/dev/ada1p2 bs=3D1g status=3Dprogress In order to overwrite data safely so these are not easily recovered you can use /dev/random in several overwrite loops, then in the last iteration you can use /dev/zero to mark partition clean (or leave random data for someone to wonder). Note /dev/random is much slower than /dev/zero. You may also use badblocks utility in destructive-write test to overwrite with different patterns and check disk condition at the same time but this will be slowest solution :-) https://man.freebsd.org/cgi/man.cgi?query=3Dbadblocks Have fun :-) --=20 CeDeROM, SQ7MHZ, http://www.tomek.cedro.info